Biology wrong answers

Describe how electrons are produced in light dependent reaction

Light strikes chlorophyll &electrons are lost, photolysis (the splitting of water), forms H+, e-, electrons replace those excited

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How does chromatography separate pigments?

Pigments have different solubilities, the more soluble, the further it travels

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Give 2 reasons why pancreas transplants are not given as treatment to type 2 diabetes patients

type 2 can produce insulin, cells are less responsive to insulin

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Explain how action potential travels down the motor neurone

Axon membrane depolarised, causing Na + channels to open in adjoining regions

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Explain how acetylcholine is released to synaptic cleft?

Presynaptic neurone is depolarised, Ca 2+ channels open and diffuse in, causing vesicles to fuse with presynaptic membrane

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Gene linkage & chi squared

State genes that are linked, state gametes produced, state what there are less of, bc crossing over has occured

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Why are males more likely to show recessive phenotype?

Males only have one gene loci, so only need one allele to present however female needs two allele to express phenotype

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Show how disease is recessive

Parents without have child with, Parents are heterozygous carriers, parents pass on recessive allele

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What does Hardy-Weinberg principle predict?

frequency of allele will stay the same, from generation to generation as long as there is no mutation, no selection or migration.

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Explain speciation

Gene pools separated limited gene flow, mutations occur, pools have different selection pressures so adapted organisms survive and breed increasing allele frequency

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Difference between allopatric & sympatric

Allopatric - geographical isolation stops gene flow & sympatric - species occupy the same area but limited gene flow

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Define Natural selection

Organisms better adapted to the environment survive, leading to an increase in some genotypes

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Describe how you would sample percentage cover

Randomly generate coordinates and sample with quadrat, have large sample size. Divide total % by number of samples

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Sucession

Pioneer species inhabits hostile environment, making environment less hostile by changing abiotic factors, increasing genetic diversity till climax community is reached

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How is the structure of DNA related to its function

Double stranded - provides strength, long molecule - store lots of information, helix - coiled & compact, base sequence - codes for amino acids, double stranded - semi conservative, weak H bonds - easily broken in replication

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Suggest how production of amino acids with one amino acid can lead to genetic disorders

Changes the tertiary structure to make it non fuctional

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Suggest how transcriptional factors can reprogramme cells to form iPS cells

TF bind to DNA, stimulating transcription

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Why is area a bad measurement for a tumour?

Tumours have different depths, should measure the volume

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Explain how methylation of tumour supressor gene can lead to cancer

Methyl group is added, which prevents transcription of gene, so no protein produced, no control of cell division forms cancer

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How does additional readings improve the graph?

Line of best fit & y intercept more reliable

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Potatoes are blotted before weighing, why?

Water will affect the mass of potatoes & amount of water on potatoes changes

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What is a monomer?

Molecules from which larger molecules are made

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Biology wrong answers

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